1. Field of the Invention
The present invention relates to a radio IC device, and more particularly to a radio IC device preferably for use in an RFID (radio frequency identification) system.
2. Description of the Related Art
As a system for managing information about articles, in recent years, non-contact communication by use of an electromagnetic field effect is performed between a reader-writer that generates an induction field and RFID tags (which are also referred to as radio IC devices) attached to articles so as to send and receive certain information. Each of the RFID tags stores certain information, and includes a radio IC chip for processing predetermined radio signals and an antenna (radiation element) for sending and receiving high-frequency signals. The RFID tags are used while being stuck to the individual articles to be managed (or the wrappings around the respective articles).
As one of this kind of RFID tags, a metal-compatible tag that operates even while being stuck to the surface of a metal article is disclosed by Japanese Patent Laid-Open Publication Nos. 2006-053833 and 2007-272264. The metal-compatible tag is fabricated by winding a metal pattern, which functions as an antenna, around a dielectric base in the shape of a rectangular parallelepiped. The surfaces of articles, which RFID tags of this type are to be attached to, have various shapes. These RFID tags need to be attachable to, for example, curved surfaces of gas canisters and the like. Such a metal-compatible tag is used while being housed in a flexible case for the purpose of protection.
However, even if the dielectric base is made of a flexible material, a bend of the dielectric base may cause stress concentration on the radio IC chip and may damage the radio IC chip.